[GtkFileChooserButton] bgo#645065 - Restore the previously-selected file when the button's GtkFileChooserDialog is canceled
[GtkFileChooserButton] bgo#645065 - Restore the previously-selected file when the button's GtkFileChooserDialog is canceled

The file chooser is asynchronous, so doing 'select_file (old_file)' and subsequently querying
the file for updating the labels is not going to work.  However, the underlying file chooser
will emit 'selection-changed' as appropriate when it finishes restoring the old file.  So,
we only need to update the labels when the file chooser dialog is confirmed, not cancelled.

davidt/gtk,alexlarsson/gtk,Lyude/gtk-,jadahl/gtk,davidgumberg/gtk,grubersjoe/adwaita,grubersjoe/adwaita,grubersjoe/adwaita,chergert/gtk,grubersjoe/adwaita,jigpu/gtk,ahodesuka/gtk,Lyude/gtk-,Sidnioulz/SandboxGtk,alexlarsson/gtk,alexlarsson/gtk,chergert/gtk,grubersjoe/adwaita,Distrotech/gtk2,Distrotech/gtk2,Adamovskiy/gtk,Distrotech/gtk2,Lyude/gtk-,davidgumberg/gtk,jadahl/gtk,bratsche/gtk-,jessevdk/gtk,jigpu/gtk,jessevdk/gtk,Adamovskiy/gtk,chergert/gtk,bratsche/gtk-,msteinert/gtk,ahodesuka/gtk,chergert/gtk,jessevdk/gtk,jadahl/gtk,grubersjoe/adwaita,bratsche/gtk-,ahodesuka/gtk,ebassi/gtk,chergert/gtk,alexlarsson/gtk,davidt/gtk,chergert/gtk,jigpu/gtk,ebassi/gtk,msteinert/gtk,msteinert/gtk,davidgumberg/gtk,Lyude/gtk-,jessevdk/gtk,davidgumberg/gtk,davidgumberg/gtk,ebassi/gtk,jessevdk/gtk,grubersjoe/adwaita,bratsche/gtk-,bratsche/gtk-,msteinert/gtk,chergert/gtk,Adamovskiy/gtk,jigpu/gtk,davidgumberg/gtk,Lyude/gtk-,jadahl/gtk,Adamovskiy/gtk,davidt/gtk,alexlarsson/gtk,jadahl/gtk,jigpu/gtk,ahodesuka/gtk,jadahl/gtk,alexlarsson/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,davidt/gtk,jadahl/gtk,jessevdk/gtk,Adamovskiy/gtk,Lyude/gtk-,chergert/gtk,msteinert/gtk,davidgumberg/gtk,davidt/gtk,Sidnioulz/SandboxGtk,jadahl/gtk,Distrotech/gtk2,alexlarsson/gtk,Lyude/gtk-,ebassi/gtk,ebassi/gtk,Adamovskiy/gtk,msteinert/gtk,davidt/gtk,Sidnioulz/SandboxGtk,grubersjoe/adwaita,bratsche/gtk-,ebassi/gtk,Distrotech/gtk2,ahodesuka/gtk,jigpu/gtk,Distrotech/gtk2,Lyude/gtk-,Sidnioulz/SandboxGtk,davidgumberg/gtk,ahodesuka/gtk,Adamovskiy/gtk,jessevdk/gtk,jigpu/gtk,ahodesuka/gtk,Adamovskiy/gtk,ahodesuka/gtk,jigpu/gtk,alexlarsson/gtk